Sister Cassie frowned. ‘One of them was pretending to be one of us. A disgusting trick, in my view.’ She described how she’d seen the pathetic figure huddled and crying under the dirty piece of carpet, and how when she went over to offer succour, the child – who was clearly not a child, at least ‘not a child in its head’ – leaped up and tried to snatch her. At the same time, she said, a vehicle, a green van, emerged at speed from the entrance to the undercroft and pulled up alongside them.

‘A green van this time?’

‘I know what I saw, child.’

‘Don’t worry, I saw it too. Or glimpsed it.’ Lucy glanced around. ‘I don’t see any carpet.’

‘No.’ The ex-nun looked for herself. ‘Perhaps the van driver took it?’

Very likely, Lucy thought. Which means that they’re forensically savvy.

‘I actually hit my assailant with the bag,’ Sister Cassie added. ‘Which is why it broke and spilled its contents. But it’s not a major problem. As you see, I can easily make repairs. But it bought me sufficient time to flee down into the basement … alas, I wasn’t swift enough to make a complete getaway.’

‘I thought the van came from down there?’

‘It was lurking down there, yes. Just like the one that took Fred Holborn.’ The ex-nun eyed Lucy carefully. ‘I know that’s what you’re thinking, child. But this one was a different colour. That one was blue, this one green.’

‘Colours can be changed, Sister.’

‘Whatever, I’d just struck my attacker with the bag when this vehicle arrived. And that was when I ran. Briefly, the underground passage was the only route open to me.’

‘Sister …’ Lucy crouched alongside her. ‘What’s going on here? I mean … what do these abductions mean? If there’s something you’re not telling us, you really need to reconsider.’

‘My dear child …’ The ex-nun put her bloodstained hand on Lucy’s shoulder. ‘You know as much as I. But as I say, here on the outskirts of society, we get attacked.’ She sighed again. ‘Sometimes, it seems like our role … that we are destined to be naught but punchbags for the less than charitable.’

‘I’m sorry to say this, but I strongly doubt this was a routine mugging.’ Lucy stood up and helped her to her feet. ‘I know it might be comforting to think that, in a bizarre kind of way. But I’m not buying it. I saw the girl who attacked you. She was wearing military-style clothing.’

‘I see.’ Though Sister Cassie clearly didn’t see, from her puzzled expression.

‘She was also fit – extremely fit.’

The meaning of this was still lost on the ex-nun, who merely shook her head with disapproval.